The intimate relation between the low T/W instability and the co-rotation point

We study the low T/W instability associated with the f-mode of differentially rotating stars. Our stellar models are described by a polytropic equation of state and the rotation profile is given by the standard j-constant law. The properties of the relevant oscillation modes, including the instability growth time, are determined from time evolutions of the linearised dynamical equations in Newtonian gravity. In order to analyse the instability we monitor also the canonical energy and angular momentum. Our results demonstrate that the l=m=2 f-mode becomes unstable as soon as a co-rotation point develops inside the star (i.e. whenever there is a point where the mode's pattern speed matches the bulk angular velocity). Considering various degrees of differential rotation, we show that the instability grows faster deep inside the co-rotation region and deduce an empirical relation that correlates the mode frequency and the star's parameters, which captures the main features of the l=m=2 f-mode growth time. This function is proportional to the product of the kinetic to gravitational energy ratio and the gradient of the star's spin, strengthening further the relationship between the co-rotation point and the low T/W instability. We briefly consider also the l=m=2 r-mode and demonstrate that it never moves far inside the co-rotation region even for significant differential rotation.Comment: 12 pages, 8 figures, 2 tables. Submitted to MNRA

Buoyancy and g-modes in young superfluid neutron stars

We consider the local dynamics of a realistic neutron star core, including composition gradients, superfluidity and thermal effects. The main focus is on the gravity g-modes, which are supported by composition stratification and thermal gradients. We derive the equations that govern this problem in full detail, paying particular attention to the input that needs to be provided through the equation of state and distinguishing between normal and superfluid regions. The analysis highlights a number of key issues that should be kept in mind whenever equation of state data is compiled from nuclear physics for use in neutron star calculations. We provide explicit results for a particular stellar model and a specific nucleonic equation of state, making use of cooling simulations to show how the local wave spectrum evolves as the star ages. Our results show that the composition gradient is effectively dominated by the muons whenever they are present. When the star cools below the superfluid transition, the support for g-modes at lower densities (where there are no muons) is entirely thermal. We confirm the recent suggestion that the g-modes in this region may be unstable, but our results indicate that this instability will be weak and would only be present for a brief period of the star's life. Our analysis accounts for the presence of thermal excitations encoded in entrainment between the entropy and the superfluid component. Finally, we discuss the complete spectrum, including the normal sound waves and, in superfluid regions, the second sound.Comment: 29 pages, 9 figures, submitted to MNRA

TRANS2CARE. Working plans: consciousness and perspective

The project started on 1st April 2011 and will end on 30th September 2014. The project received a budget of \u20ac 2,611,118 from the Italy-Slovenia 2007-2013 Cross-border Cooperation Programme. Seven universities and research institutions, five hospitals and a center for technology transfer distributed over the Programme area constitute the \u201cInterregional network for innovation and technology transfer for health improvement\u201d, which will continuously develop new protocols and biotechnological devices for the prevention, early diagnosis and treatment of neurodegenerative, cardiovascular, orthopaedic and oncological diseases

On the magnetic field evolution timescale in superconducting neutron star cores

We revisit the various approximations employed to study the long-term evolution of the magnetic field in neutron star cores and discuss their limitations and possible improvements. A recent controversy on the correct form of the induction equation and the relevant evolution timescale in superconducting neutron star cores is addressed and clarified. We show that this ambiguity in the estimation of timescales arises as a consequence of nominally large terms that appear in the induction equation, but which are, in fact, mostly irrotational. This subtlety leads to a discrepancy by many orders of magnitude when velocity fields are absent or ignored. Even when internal velocity fields are accounted for, only the solenoidal part of the electric field contributes to the induction equation, which can be substantially smaller than the irrotational part. We also argue that stationary velocity fields must be incorporated in the slow evolution of the magnetic field as the next level of approximation.Comment: 6 pages, version accepted by MNRA

Entry of the University of Trieste in the Cross-Border Cooperation Programme Italy-Slovenia 2007-2013

The CBC Programme Italy-Slovenia 2007-2013 and the University of Trieste: correspondence between Programme\u2019s objectives for the European territorial cooperation and the institutional University missio

Il sistema della ricerca biomedica transfrontaliera italo-slovena: un elemento strategico di specializzazione intelligente per la politica di coesione 2014-2020

Il sistema della ricerca biomedica. Il cospicuo patrimonio d\u2019infrastrutture, tecnologie e conoscenze biomediche presenti con alta densit\ue0 in area transfrontaliera s\u2019inserisce in un quadro strutturale evidenziato come un elemento di forza nell\u2019analisi SWOT del Programma Operativo Italia-Slovenia 2007-2013. Grazie ai finanziamenti erogati dal Programma per la cooperazione transfrontaliera Italia-Slovenia 2007-2013, la ricerca biomedica ha avuto un notevole impulso, creando e rafforzando le collaborazioni in rete transfrontaliere (e trans-regionali)